Career criminal Arthur Taylor will take his case to end a ban on prisoners voting to the High Court in Auckland today.

Arthur Taylor Photo: RNZ / Kim Baker-Wilson

Mr Taylor is seeking to have the election result in John Key's electorate Helensville overturned, saying the prisoners at Auckland Prison, which is in the electorate, were denied their voting rights.

He has the backing of prisoner advocates and electoral law experts, who said his bid was unlikely to succeed but put the spotlight on a piece of bad legislation that should be scrapped.

Mr Taylor had already lost one court bid last year, right before the general election, to have the ban on prisoners voting ruled unlawful.

He argued that the right to vote was entrenched - requiring a 75 percent majority in Parliament to change.

Justice Ellis found that the only thing that was entrenched was the voting age of 18, and so had to dismiss his case.

But she used her court judgment to spell out in detail the various criticisms of the law, calling it "constitutionally objectionable", and wrote that Mr Taylor was "not some vexatious voice in the wilderness" on this issue.

"I think it is important to record that there is considerable, and considered, support for the position he is advancing."

Otago University law professor Andrew Geddis, who specialises in electoral law, said the judge's comments were an unusual step.

"She could have just simply said, look, here is the law, it's clear on its face and I have to do what it says," he said.

"So the fact that she chose to go through all of those issues and to highlight them right at the very start of her judgment is done for a purpose.

"And the purpose is to draw the reader's attention to it, so there's no one who can look at that judgment [who] comes away with anything but the understanding that the judge thinks this law really is a dog."

Prisoners were disqualified from voting by the Electoral Amendment Act 2010, put forward as a member's bill by then-National MP Paul Quinn and passed with a two-vote majority.

Previously, all prisoners serving a jail term of fewer than three years could vote.

The slim majority combined with a lack of scrutiny was a disgraceful way to deny a whole group of people a fundamental democratic right, Mr Geddis said.

But Mr Quinn said he still stood by the law he created.

"My view, and Parliament accepted, is that one of the rights you should lose is your right to vote. Having committed a serious crime against society deserving of prison, why should you continue to have a say on how society should live?"

Rethinking Crime and Punishment director Kim Workman said that argument flew in the face of the Corrections Act, which aimed to rehabilitate prisoners.

"It wasn't about reducing the re-offending, it wasn't about helping prisoners to re-integrate safely back into the community - it was a means of further punishing prisoners, beyond that punishment imposed by the courts."

Mr Geddis agreed and said, regardless of the outcome of Arthur Taylor's court hearing, Parliament should scrap the ban - and tighten up other voting rights at the same time.

"One is the right to vote, wholesale. I just think it's crazy that, even in theory, a majority of MPs could take the rights of women to vote or the right of people in Southland away."